In the general tropospheric tomography model, the tomographic area is divided into a large number of voxels, which provides convenience for reconstructing tomographic observation equations. However, due to the defect of GNSS acquisition geometry, there are plenty of empty voxels for any tomographic epoch. Moreover, an unreasonable assumption that water vapor density is constant within a voxel was imposed on the tomographic model. In this study, we proposed an improved method based on the dynamic node parameterized algorithm to solve both key problems. The proposed approach first tries to select effective GNSS signals and determines the dynamic scope of the tomographic area using the dynamic algorithm. The parameterization of the tomography model is performed by a cubic spline formula and Gauss weighted function. Additionally, a piecewise linear fitting method based on Newton-Cotes interpolation is introduced to estimate the tomographic observation of slant water vapor (SWV). The experimental results show that the average number of effective signals increased by 32.33 % and the mean RMSE of the tomographic results is decreased by 45 % with the proposed method. Further, compared with the tomographic results of the general method, the improved solutions have a more centralized distribution and a smaller bias., Wenyuan Zhang, Shubi Zhang, Nan Ding and Pengxu Ma., and Obsahuje bibliografii
GNSS meteorology is the remote sensing of the atmosphere (particularly troposphere) using Global Navigation Satellite Systems (GNSS) to deliver information about its state. The two currently available navigation satellite systems are the Global Positioning System (GPS) and the GLObal'naya NAvigatsionnaya Sputnikovaya Sistema (GLONASS) maintained by the United States and Russia, respectively. The Galileo navigation satellite system, which is under supervision of the European Space Agency (ESA), is expected to be completed within the time frame of a few years. Continuous observations from GNSS receivers provide an excellent tool for studying the earth’s atmosphere. The GNSS meteorology has reached a point, where there is a need to improve methods not only to compute Integrated Water Vapor over the GNSS receiver, but also to investigate the water vapor distribution in space and time (4DWVD). Since 2008, the new national permanent GNSS network ASG-EUPOS (98 stations) has been established in Poland. 17 Polish stations equipped with GNSS receivers and uniform meteorological sensors work currently in the frame of the European Permanent Network. This paper presents the concept of the integrated investigations for NRT atmosphere model construction based on the GNSS and meteorological observations from ASG-EUPOS stations., Jarosław Bosy, Witold Rohm and Jan Sierny., and Obsahuje bibliografii